Easy question for history​

most people now work in jobs where they do one  kind  of work; they are carpenters, bankers, cooks, mechanics, and so forth. likewise, most  businesses produce  only certainkinds  of  goods  or  services, such as cars, tacos, or gardening  services. this feature of  production  is known as specialization.

it would be a. that is the only one i could think of

copernicus finished the first manuscript of his book, "de revolutionibus orbium coelestium" ("on the revolutions of the heavenly spheres") in 1532. in it, copernicus established that the planets orbited the sun rather than the earth. he laid out his model of the solar system and the path of the planets.

according to my calculation, the answer is d.